Drain on car battery


My wife has a mid mileage 1995 ford probe has been good vehicle.

Last fall when it sat for over 24 hrs the battery would discharge and wouldn’t start.

Last fall I put a full charge on the battery and disconnected the grd cable.

We went to Florida for 5 months & returned in the spring.

Reconnected the grd cable and car started rite up with a strong battery.

Two days later the battery was not strong enough to start car.

I took it to the mechanic in the local garage who has serviced the car & asked him if he could isolate the drain.

After 3 weeks of trbl shooting (removing fuses, cleaning cables & grds,rmving radio) he ntfd me he was at his wits end. He installed a bypass switch on the grd cable that opened up the grd cable and this works fine except my wife has to open up the hood everytime to open or close the switch.

He did all this with no charge after spending a considable amout of time on the problem. I consider him & his crew as top mechaics.

I called Ford & totally no help what so ever except to say bring it in at $106 dollars & hr for labor. This is where I bought the car.

Any ideas or suggestions most appreciated!


I had a similar problem and after much fooling around found the glove box light was staying on. Removed the bulb and no more problems. Was suprised the little bulb drained the new DieHard as quickly as the one it replaced. Found it by measuring current draw from battery with engine and accessories off. jkd, Beautiful Golden, Colorado


My dad had the same problem with a 1973 Oldsmobile Cutlass Sport that he bought second hand. If the car sat for a couple of days, the battery was too low to crank the engine. He took it to a shop in our town that specialized in electrical problems. He figured that the shop had seen this car before when the service technicians all dived into empty oil drums. At any rate, they ran all kinds of tests, but couldn’t find the problem. One evening, when the battery was too low to start the engine, he asked me to come over and bring my battery charger. I came over and we connected the battery charger and drank a couple of beers. After a couple of hours, he suggested we try starting the car and it started. I decided to look for the problem. I turned off everything in the car, removed the negative cable and then scratched it against the terminal. I got a pretty good spark to arc between the post and the cable. I reconnected the cable, and decided to pull fuses. I put my head under the dashboard and as I was looking at the fuse panel, I noticed a glimmer of light around the console. The switch for this light was stuck on. I removed the bulb and that solved the problem. Since you apparently are not blowing fuses, something is probably staying on when it should be off. You might try removing the bulbs from the console if the car has one, the glove compartment light, trunk light, and even the bulbs from the vanity mirrors on the sunvisor if the car is so equipped.

Some cars also keep some of the accessories powered for 10 minutes or so after the ignition switch is turned off before a door is opened. If your car is set up this way, the next time you stop, leave the radio on and see if it eventually turns off. If it doesn’t, it may be in this circuit.


This is not rocket science. You put a amp meter on the system and start pulling fuses until you find the one that kills it. The only time that does not work easy is when you have some sort of intermittent drain like a air pump for a air suspension that kicks in when it should not.


It would be nice to know what things your mechanic checked. One area he may have missed is the alternator circuit. Sometimes a blocking diode can short and allow current to drain from the battery.

I recommend you take the car to a shop that specializes in electrical repairs. They should be able to find the trouble quickly.


Besides the alternator, the starter solenoid is another place a short can occur. At night, after the car has been driven, sneak up on the car and listen for hums and buzzes, and look for lights. Sometimes, a radiator cooling fan relay will energize and turn a fan on 'way after the engine has cooled. If that happens, change the fan relay.


I have to go with the alternator also.It could be the built-in regulator sticking.I had a couple of cars over the past five years that has done this and it was the reg. both times.[THEY WERE FORDS ALSO]